A Numerical Study on Flows Over Two-Dimensional Simplified Vehicle-Like Body

단순화된 2차원 자동차형 물체주위 유동에 관한 수치해석적 연구

Turbulent flows around two-dimensional vehicle-like bodies in ground proximity are numerically simulated. The Reynolds averaged Navier-Stokes equations with a k-.epsilon. turbulence model are numercally solved, and a body-fitted coordinate system is used. It is shown that the simulation is acceptable in comparison with limitted data measured in the wind-tunnel. According to numerical simulations, drag coefficients are under-estimated and lift coefficients are over-estimated during the model test in the wind-tunnel if the ground is fixed. Such ground effects are reduced as Reynolds number is increased. Reducing the gap between the vehicle and the ground make drag coefficients smaller and lift coefficients larger. The changes in static pressure distributions on the bottom and the rear surface play dominent roles in determination of the drag and the lift of the body in ground proximity. Drag component less than 10% of the total amount is contributed by skin-frictions. When the slant-angle of the body is reduced, the drag shows its minimum value and the lift shows its maximum value at about 22 degree.

본 논문에서는 유정열 등에서 수행된 단순화된 자동차형 2차원 물체 주위의 유동에 관한 실험적 연구와 병행하여 이루어진 수치해석적 연구의 일부와 계속된 일련의 연구를 다루었다. 수치해석은 ｋ-.epsilon. 난류모델과 body-fitted 좌표계를 채택하여 수행하였으며, 우선 수치계산의 합리성 및 문제점을 파악하였다. 이어서 지면효과와 물체 후미의 경사각의 영향에 대하여 수치해석적으로 연구하였다.